Overlapping Generations Model
Overlapping Generations Model (OLG) · Also known as: OLG Model, Diamond Model
The Overlapping Generations Model, pioneered by Paul Samuelson in 1958 and extended by Peter Diamond in 1965, is a macroeconomic framework where successive generations of individuals live for finite periods and coexist at any point in time. It addresses how consumption, savings, and capital accumulation evolve across generations and how monetary and fiscal policy affects intergenerational distribution.
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When to use it
Use OLG when analyzing long-run fiscal sustainability, the macroeconomic effects of demographic change, or intergenerational equity of government policies. It is essential for studying pensions, public debt, and capital-income taxation. OLG is less suitable for high-frequency business-cycle analysis; use it when the lifecycle dimension or intergenerational transfers matter.
Strengths & limitations
- Explicitly models intergenerational distribution of resources and wealth.
- Provides a natural framework for analyzing fiscal and monetary policy effects on welfare.
- Can explain empirically realistic savings behavior and wealth inequality across age cohorts.
- Accounts for endogenous capital accumulation and its effect on future generations.
- Computational complexity increases sharply with more than two or three periods per life.
- Finite-lived agents make aggregate dynamics less stable than infinite-horizon models.
- Calibration requires detailed age-specific data on income, consumption, and wealth.
- Heterogeneity across agents (by ability, family size) requires sophisticated solution algorithms.
Frequently asked
How does the OLG model explain why people save for retirement?
Agents are born with no wealth and work when young, earning wages. They save some of their wages to finance consumption when old (after retirement). The interest rate on savings reflects the return to capital; higher returns make saving more attractive. This creates an endogenous demand for capital and government debt.
Can the OLG model be extended to more than two periods per life?
Yes, but with increasing computational cost. Three-period models (childhood, working years, retirement) are common in applied work. More periods allow richer age-dependent income and consumption profiles but require numerical solution methods rather than closed-form analysis.
What is the difference between OLG and Ramsey models?
Ramsey models assume an infinitely-lived representative agent. OLG models assume agents live for a finite number of periods. This difference is critical: in OLG, government debt and pensions create real intergenerational transfers and can affect capital accumulation, whereas in Ramsey models, rational agents fully internalize the burden on future generations.
How does the OLG model account for government debt?
Government debt is an asset that current and future generations hold. When issued, it increases current consumption (via deficits) but imposes a burden on future workers (who must pay higher taxes to service the debt) or future retirees (whose benefits are reduced). The OLG framework naturally traces these intergenerational effects.
Sources
- Diamond, P. A. (1965). National Debt in a Neoclassical Growth Model. American Economic Review, 55(5), 1126–1150. link ↗
- Samuelson, P. A. (1958). An Exact Consumption-Loan Model of Interest with or without the Social Contrivance of Money. Journal of Political Economy, 66(6), 467–482. DOI: 10.1086/258100 ↗
How to cite this page
ScholarGate. (2026, June 3). Overlapping Generations Model (OLG). ScholarGate. https://scholargate.app/en/economics/overlapping-generations-model
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
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